Why would the culture of a country influence the cost of doing business in that country?

One example is that the British are more formal - so showing up in white socks and Birkenstock s would certainly affect a business deal. Their national holidays are not the same as ours. Don't expect workers to come to work on 12/26, due to Boxing Day, which is also a national holiday. As is the 3 or 4 of May.

In many Islamic countries, Friday is the holy day, not Sunday. As such, this may affect scheduling business transactions between a christian country and an Islamic country.

Another example is in Egypt. Workers will only work 6 hours a day during the holy month of Ramadan. This is not a cultural difference your business could afford to eschew, as it is also the law there. This would affect productivity of any businesses you had there, as well as the timing of business deals.

Many countries have different requirements for providing gifts, and etc. Also, many cultures are wary of working with unfamiliar businesses, so money and time would have to be spent in building relationships with them, as well as possibly with an intermediary.

The source I cited should give you some profit.